Heating of fluid



April 11, 1944. L.. A. MEKLER HEATING oF FLUID Filed oct. 51 1941Patented Apr. 11, 1944 lrnill'ijrrtc. oF FLUID Lev A.'Mekler, Chicago,Ill., assgnor to Universal Oil Products Company, Chicago, Ill., acorpora- I l tion of Delaware Application October 31, 1941, Serial No.417,337

s claims. (C1. 19e-47) The invention relates, to an improved method andmeans of heating nuidsthe preferred form of apparatus provided by theinvention'being of the general type now known in the art as an equinuxheater and the process beingparticularly directed tothe simultaneousheating of separate streams of the same hydrocarbons, each undersubstantially the same heating conditions. It is particularlyadvantageous as appliedto rheating hydrocarbon oils or gases to the hightemperatures required for Vtheir simultaneous thermal orsubsequentcatalytic conversion, with low pressure drop through the heating coil. I

VThe term equinux type heater, as herein used refers to the`general formofnheatenlnow widely used in the oil renning industry, of single ormultiple cell construction, each cell contain; ing a vertical bank ofhorizontally disposedtubular fluid conduits, each of which issubjectedto `high rates of Vheating on the opposite sides thereof by` heatsupplied thereto from adjacent substantially parallel refractory Wallsheated to a radiant condition by flames and hot combustion gases4passed,i-,hereover in ausubstantially vertical direction, theQppositesidesofsaid tubes also receiving heat by radiation andAconvection from said names and hot combustion gases.

The heater herein providedmay, within the scope ofthe invention,befeither upwardly or downwardly fued and in (211.8,..Speci1 .embpdimentvcomprises two equinux cells, `each of the tube banks disposed in s aidcells comprisingtwo adjacent vertical frowsof horizontal tubes disposedcentrally within the cell and adjacent tubes in opposite rows of thesame bank being arranged in staggered formation. Combustion gases, whichhave been cooled substantially by the heat transferred therefrom to` therefractory walls over which they are passed and to the tubular elementsof the equinux banks, are directed from each of the separate cellsthrough `a separate nuid heating zone directly communicating` with therespective cells. 'Ifwo separate tube banks, each vcomprising aplurality of `superimposed hor-v izontal rowsofvhorizontally disposedtubes, are located in each of saidrfluid heating zones. ,Y In accordancewith the preferred mode of operation provided by the. invention, themain stream of oil orother nuid toebevheated is divided into fourseparate streams of substantially equal volume. Each Aof, said separatestreamsis passed through one of the banks of tubular conduits disposedin said nuidheating zones. Two streams'which have passed,respectivelxr-,through one of the nuidlheatingbanks inthe .separate nuidheating zones are thence commingled and the commingled stream is passedin series throughl one row of tubes in each of the equinux banks, theother two separate .streams of nuid, which have passed,respectively,1through one of the nuid heating banks in the separate nuidheating zones being likewise commingled and the resulting commingledstream passed ln series through the other two rows of the equinux tubebanks. Y l

The accompanying drawing diagrammatically illustrates a cross-sectional`elevation of a twocell heater embodying the features of the in-`vention. Y-

Referring to the drawing, theheater is provided with a foundation I uponwhich a plurality of steel columns 2 supporting steel beams 3 aremounted. Refractory shapes which form the side walls 4 and 5 and theroof 6 of the heater are suspended from the Asteel framework in anyconventional manner, not illustrated.

A vertical refractory wall l, resting on the foundation and extending tothe roof and between the end walls of the heater. is disposedsubstantially mid-way between the side walls 4 and 5 and divides theinterior of the upper portion of the heater into cells A and B.y CellAAofthe heater comprises combustion and heating zones 8 and 9 disposed,respectively, between side wall 4 and the equinux tube bank I2 andbetween wall l and bank I2. Cell B of the heater is, in this particularinstance, substantially identical with cell A and comprises similarcombustion and heating zones I 0 and Il disposed, respectively, betweenwall 'l and the equinux tube bank I4.

On the left-hand side of the heater, as illustrated, refractoryfwalls I6and I1, which denne thenuid heating zone 20, `slope, outwardly adjacenttheir upper ends to -joln walls 4 and l respectively. On the right-handside of the heater, as illustrated, similar refractory walls. I8r andI9, which denne, nuid heating zone2l, slope outwardly adjacent theirupper ends lto join walls 5 and l respectively. Fluid heating zone 2D isdisposed substantially mid-way between and beneath combustion andheating zones 8 and` 9 and directly communicates at its upper end withboth of these zones.. Fluid heatingzcne 2l is. disposed substantiallymid-way between and-beneath combustion and heating zones I0 and l-I andcommunicates atfits upper end with both of these zones. l l

The equinux-tube bank l2 in1ce11 A comprises two vertically intrallel`rows ofhorizontally disposed tubes I3 with the tubes iii-opposite rowsarranged in staggered formation, the tube bank being disposed centrallybetween walls 4 and I.

. The equiflux tube bank I4 in cell B, in the particular case hereillustrated, is substantially the same as tube bank I2 of cell A and,like the latter, comprises two vertically parallel rows of horizontallydisposed tubes I5, tube bank I4 being disposed centrallyrbetween wallsAand,. 'I.

Two separatetube banks 22 and'23," 'each comprising a plurality ofsuperimposed horizontal rows of horizontally disposed tubes, aresubstanf tially identical in ferm and are located side by side in fluidheating zone 20.

Two separate similar tube banks 24 and 25, heach comprising a pluralityof superimposed ho u rows of horizontally disposed tubes aresubstantially identical in form and arelocated side by side in fluidheating zone 2 I.

A row of firing ports 26 is provided in the roof of the heateradjacenteach of the side walls 4 and 5 ane'adj'acerit' opposite sidesofthe centrar wan 1. 'cori espoiiciiiig -fetvs of burners n Suppl-y fu"rid fair to each of theoinbustion and heatingonejs''s; 9,f `|`0 andiII.The quantity of corri'- bils'tible' f u'el 'and'ar supplied to `"eachcombustion Zoffeis jndiilld'elfrtlfy'regulted 'and the inventionspfedically` contemplates controlling the burners to "maintain'substantially equal heating 'conditions Ton opposite sides Vof fthe'tube banks in' the respective cells and to maintain different heatingconditions intheitwb'b'ellsfAand'B. The burners andfiring p" "are soerranged-thatflames and ht Combustin igases, ''sltirigri'n Combustion ofthe fuel, are directedin a substantiallycontin'ubus 'slieet downwardlyover the inner faces of-Ftheirefractryfside fw'alls T4II fand 5and'downwardly vover 'the''oppfsite' faces of the refractory centralwall'I," hatingjthese l'refractory surfaces to a nighiy '"iadiaiiticonditionand keeping tube harias r2 'and T4 'ebt-of 'the direct patri of knew ofthe amesiad combustin fg'ases:-

lnach of tire tubuia'rfeienints l'aandi'sor-the respective toiiflu'xftube "banks I2 and lIII receivsineat oiiibotnsiues 'by radiation fromthe niedwaus of lcells VA Cand 'B *andfdifeotiy from uis 'nainesansi-noi coiiibiistionjgases passing downwardly theiove r. considerati@iiiiiu heat is iiss impartedfroiiitiieeoiiibiistionfgases to thetubularfeiemiitsjfiuanks=1= afm. l The combustiongasesj chf'have--givenup a substantial portion of their neat fio th 'tubular tubular elementsco'rnl'oustion5 gases from "zone's I 0' arid I"Iv arepassed thlugh'zone2| and supply"hat-tbthe vtubular elerrientsbf-"b'an'ks24A andf25.'Fromfluid heating zone 2D 'the' combustion Jgases V--pass 'throughflue-"28 to'a suitable stack, not illustrated, and

fronllui'd heating 'zne 2| ,the combustion 'gas'es pass through flue'29" tothe stack.

' The Aflow of oil 'o 'rf'other uid to be heated through 'the Yvarioustube banks of the 'heater-ile genralvetrata;dreetinimmergere@ te thedirectioifi jof -'tr ave1 ofr the'fcombusticn vgasesthrough'huiddieatingzones 20 :and i2I.

ofibanks'zfa'n'd 23. similarly, f

directed through conduit 34, located outside the main furnace structure,to the upper tube of the Kleft-hand row of bank I2 and passes in ageneral downward direction in series through adjacent 'tiibe'sfbfconcurrent to the general direction o'fmfow vof lthe flames and hotcombustion gases passing through cell A, to be dis-`char''gedfromtlielowermost tube of this row and unite in dischargeconduit 36, located outside the main furnace structure, with anotherstream of the saine /flui'd fof' substantially equal "volume yand heatedunder substantially "identical conditions, asv 'will 13e-now' described.

Thestrean 'of-"fluid heatedf-intubebank 2 3 passsf throughline32Lflbcatd1tsidethe main furnace structureirito -line 133'-,als'o-ldcated' outside the inaiiffiiinacestuctur "'wherein 'it iscomfmin'gled 'with the stlreamfof -liiiid #heated 'in tube 'bank25"arid"tlie niniingled'stam passes in'a general upward@ eetl'-iiis'eris through adjacent tubes in thev countrcuret tot iiux heater,neither the apparatus provided by the invention nor the method ofheatingwhich it-,afforda is limited to heaters of this type. f lhefeatures of the invention will be found advantageous `in heaters of manydifferent forms whichthave separate, heating zones and particularlythose of the class having two ory more radiant heating zones operatedunder either substantially the same orv different heating conditions andhaving two or more fluid heating zones wherein different heatingconditions prevail.` l I claim as my invention: s l

1. A heater for fiuids comprising, in combination, a pair of separatecombustion and radiant heating zones having substantially parallel,vertically disposed side walls, two substantially parallel, verticalrows of horizontal tubes disposed in each of said radiant heating zonessubstantially midway between said side walls thereof, independentlycontrolled firing means for each of said radiant heating zonescomprising burners disposed to project flames and hot combustion gasesvertically over said side walls in direct heat radiating relation to thetubes f said banks, a separate iiuid heating zone communicating witheach of said radiant heating zones to receive combustion gasestherefrom, a pair of tube banks arranged in each of said fluid heatingzones to receive substantially equal heating from the combustion gasespassing through the respective fluid heating zones, each of the lastnamed banks comprising a plurality ol superimposed horizontal rows ofhorizontally disposed tubes, means for passing separate substantiallyequal streams of the fluid to be heated in parallel through the severaltube banks in the fluid heating zones, a tube bank in one fluid heatingzone being manifolded with a tube bank in the other iiuid heating zoneand the other tube bank in the first fluid heating zone being manifoldedwith the other tube bank in the other fluid heating zone, one of saidmanifolded pair of banks being connected in Series with one row of tubesin one of the radiant heating zones, the other manifolded pair of banksbeing connected in series with the other row of tubes in the last namedradiant heating zone and each row of tubes in the last named radiantheating zone being connected in series with a separate row of said tubesin the other radiant heating zone.

2. The method of heating fluids which comprises, heating a plurality ofseparate, substantially equal streams of fluid under substantially equalheating conditions, separately heating a plurality of separatesubstantially equal streams of the same fluid each under substantiallyequal heating conditions dierent from those to which the rst namedseparate streams are subjected, thereafter commingling separate streamsfrom each of said groups to obtain a lesser number of separate streamseach of substantially the same temperature, and separately furtherheating the last named streams each under substantially equal heatingconditions.

3. The method of heating fluid hydrocarbons to a high conversiontemperature which comprises, heating a plurality of separatesubstantially equal streams of hydrocarbon fluid to below saidconversion temperature under substantially equal heating conditions,separately heating a plurality of separate, substantially equal Streamsof the same hydrocarbon uid to below said conversion temperature eachunder substantially equal heating conditions different from those towhich the rst named separate streams are subjected, thereaftercommingling separate streams from each of said groups ,to` obtain alesser number of separate streams each of substantiallythe sametemperature and separately further heating each of the last namedstreams to said conversion temperature .under substantially equalheating conditions. A

4. The method of vheating iiuids which comprises, heating a, pluralityof separate, substantially equal streams of fluid under substantially-equal heating conditions in a fluid heating zone, separately heating aplurality of separate streams of the same fluid each under substantiallyequal heating conditions in another uid heating zone wherein theconditions of heating are different from those maintained in the nrstnamed fluid heating zone, thereafter commingling separate streams fromeach of said groups to obtain a lesser number of separate streams eachof substantially the same temperature, and separately further heatingeach of the last named streams under substantially equal, more severeheating conditions by passing the same through fluid conduits exposed todirect radiant heat.

5. The method of heating fluids which comprises heating a plurality ofseparate, substantially equal streams of iiuid under substantially equalheating conditions in a iiuid heating zone, separately heating aplurality of separate streams of the same fluid each under substantiallyequal heating conditions for each stream in another fluid heating zonewherein the conditions of heating are different from those maintained inthe first named fiuid heating zone. thereafter commingling separatestreams from each of said groups to obtain a lesser number of separatestreams each of substantially the same temperature, separately furtherheating each of the last named streams under substantially equal, moresevere heating conditions in a radiant heating zone from whichcombustion gases are supplied to one of the aforementioned fluid heatingzones, and subsequently heating each of the last named separate streamsunder substantially equal heating conditions for each stream in anotherradiant heating zone in which different heating conditions are employedfrom those maintained in the rst named radiant heating zone and fromwhich combustion gases are supplied to the other of said fluid heatingzones.

6. The method of heating fluid hydrocarbons of high conversiontemperature which comprises, heating a plurality of separate,substantially equal streams of hydrocarbon uid under substantially equalheating conditions in a fluid heating zone, separately heating aplurality of separate, substantially equal streams of the samehydrocarbon fluid, each under substantially equal heating conditions foreach stream in another iiuid heating zone wherein dierent heatingconditions are employed from those maintained in the first named fluidheating zone, thereafter commingling separate streams from each of saidgroups to obtain a lesser number of separate streams each ofsubstantially the same temperature, separately further heating the lastnamed streams each under substantially equal heating conditions in aradiant heating zone from which combustion gases are supplied to one ofsaid fluid heating zones, and subsequently heating each of the lastnamed separate streams each under subq stantal-ly vequal heatingconditions for each stream in' another radiant heating zone fromiwhiencombi-istif'ml gases-are supplied tothe other 'uidlheating zone,and -rna-intainingy different heating `conditions' in.- thel two radiantheating zones.

f 7i 'heater for'uids comprising, in combination; separate radiantheating zonesV each-pro* videdwith'independentlycontrolled firing meansseparate banks of 'fluid conduitsin each ofi said radiantAheatingfzones, a fluid heating zone individi-iai to and communicatingwith eachA of Vsaid radiant-heating zones to'receive combustion gasestherefrom; separate banks of lfluid conduits;- in each 4of said'=y"fil'rid'hea-tingV zones; said separate banks 1in--eachv of lthe heatingzones bei-ng con structedand arranged for the flowof-"af separate streamoffluid through each, individualf banks in separate radiant` heatingAzones being lconnectedv'nseries, individual-banks in separate fluidheating zones-being manifolded in'y parallel, and the manifolded 'banksbeing connected in series with the-banks Vof fluid conduits in one ofthe separate'radiantheating zones.

8. Ai heater such as Ydei-inedv inclaimv'7, wherein said ringfmeans;fluid conduitsV and ea-'ch of said heating 'zones are constructed andarranged to aord substantially equal heating for each of said separatebanks disposed within the same heatingzone.

Y LEV A.l MEKLER;

